Stock Car Safety - A Refresher Course

1/13We can learn a lot from history, or we can let it repeat itself. Here we will take a look at stock car safety, from a past perspective, the present and into the future.

There is no such thing as a safe racecar. Racecars are designed to go as fast as possible within the limits of the applicable sanctioning rules and the laws of nature. There will certainly be safety problems that come with that whole scenario. What we can do is try to make our cars as safe as possible and hope for the best. We can always have a safe-er racecar.

Some of the material presented here you might have seen before, but as in many aspects of racing technology, we need to be reminded often about areas of special concern, and safety is a very special area. We will concern ourselves with the higher priority items, ones that can be fatal.

While there have always been fatal accidents in racing, there are certain periods that stand out. The '80s in Northeast modified racing saw quite a few fatalities until someone caught on that the framerails were way too stiff. Although I don't know the exact cause of death in each instance, one can assume that Basal Skull fracture was associated with many of those because of the many head-on impacts involved.

2/13This stock clip front end has a lot of bends and angles designed into it. This is not by accident (excuse the pun). Manufacturers have long been aware of the importance of crush zones and energy absorbing that is needed to be designed into a car to help the occupants survive hard crashes.

The years 1999 through 2001 saw numerous driver fatalities from impacts with concrete walls. Of course, the most well known involved Dale, Sr. That one event caused the ground to shake in every racing community, stock car especially. I do believe Dale's tragic end was a catalyst that might well have saved many lives since. Many sanctions and tracks now require head and neck restraints and some tracks now have soft walls installed.

Looking at the possible causes of the problem, there was a reason why all of a sudden, drivers were not able to withstand the force of impact for each of these periods. Something changed along the way that caused the impacts to affect the driver more severely.

In the time since 2001, we might have suffered more deaths in stock car racing, as well as other forms of automobile racing, had events not unfolded like they did. Everyone inside and outside the sport of auto racing had come to realize that something needed to be done to make this sport safer for the drivers. And they did.

3/13The rear frame member on a stock passenger car is curved like the front. Rear end impacts are cushioned and the deformation of the frame lessens the g-forces transferred to the occupants.

Before 2001, talk centered on soft walls. Most of the talk about making stock car racing safer had been centered on designing a soft wall technology and virtually no one was mentioning the construction of the cars as a possible cause-until February 20, 2001, two days after Dale's crash. That day a story was published in the Daytona Beach (Fla.) News-Journal paper by Godwin Kelly, the paper's motorsports editor, that shed light on the root of the problem.

In that article, experts pointed out that it was possible that the cars had become too stiff whereby the forces from near instant deceleration were transferred excessively to the driver. The weak point is the base of the skull and that is the only part of the body that holds the head from moving forward. In sudden deceleration, the tendons and muscles are not strong enough to counter those huge forces and they break. When they do, massive damage is done to the spine and base of the brain causing death.

As a result of that period, racers have come to understand the risk they take in all forms of racing by not protecting the head from sudden forward motion. And so the Head and Neck restraint was developed by several companies to assist in controlling the violent forward motion of the head in a crash.

4/13Modern test equipment such as this one help us design better helmets. But as good as we get at improving the various parts and pieces, we still need to manage the magnitude of the impacts through proper construction techniques. When was the last time you heard a chassis manufacturer tout the safety aspects of their cars? Probably never.

The use of head and neck restraints since that time has become almost the norm among drivers. We have, for the most part, eliminated basal skull injuries among those drivers who religiously wear the devices.

I witnessed a crash in 2006, where I am certain there would have been serious injury or death, in a Late Model practice. It was at the high-banked and fast I-70 Speedway during an ASA Late Model Series practice session. A driver blew a right front tire and impacted the wall with the front of the car. He hit so hard, he was knocked out. The car rebounded off the wall and was sitting in the middle of the track, facing traffic. Another car, going very fast, hit him head on again. This second impact was as bad, or worse, than the first.

His helmet was crushed at the inside front, leading experts who examined it to speculate that the combined impacts were well in the fatal range. The driver was wearing a Hans device and survived to race again. It is situations like these that drive home the argument that we need these kinds of safety equipment every time we get into a racecar.

he article previously mentioned suggested that we might need soft cars instead of soft walls and told how the construction of stock cars has evolved over the years. Many stock cars are not able to crush sufficiently in order to absorb the impacts with concrete walls. As a direct result of that story, a lot of attention has been directed toward understanding the problems associated with the construction of chassis.

5/13The front of our NASCAR Late Model stock car has an angle built into the front of the main framerail. This provides some angular deflection when and if the car impacts the wall. The bracing out to the front valance could be stronger in most cars too in order to start the process of energy dissipation early in the crash event.

The problem with stiff cars wasn't just a "big league" problem, it had become an industry-wide stock car racing problem. In certain years, too many short track drivers lost their lives from either basal skull fractures or massive head injuries, as described in the news accounts of those events.

The injuries seem to point toward chassis that were too stiff. These horrible losses are not acceptable and tell us clearly that the whole of the industry needs to take a good look at how the cars are constructed and the car builders and teams need to make changes where necessary.

The stiffness associated with the construction of the cars and trucks in all stock car divisions, tended to evolve over a period of more than 15 years. In mid-1980s, major-league stock car teams were allowed the use of a rear suspension system called the "Truck Arm" system. It is essentially a copy of a mid-60s Chevrolet C-10 pickup truck rear suspension. It was strong, it had some good performance characteristics, but this system basically upset the balance of the racecars so that the setups were harder to develop and driving the cars was more difficult than even some of the older designs.

6/13Stock car safety extends to the whole race crew. Making sure to put jack stands under the car when the crew is working beneath it is not just a good idea, it is essential. I have many times gone and fetched stands when I see a crew member crawl under a car that is supported only by a pump jack. I refuse to stand witness to that kind of accident.

In order for a stock car to handle correctly through the turns, it must have a balanced setup. We know now, due to technological advancements, that the term "balanced" means that both ends of the car will desire to do the same thing in the turns at high speeds. The setup in a stock car is correct when both ends are made to want to do the same thing.

Because stock cars were becoming more difficult to balance, the culprit was thought to be chassis flexing, or compliance as referred to by some of the top Cup engineers of that period. In order to "fix" the problem, designers of the chassis started to stiffen the cars from the right front to the left rear. This really didn't help much, but it did get out of hand. The real culprit was the basic design of the suspension systems, but that escaped most of the engineers.

From approximately 1995 on, the teams and car builders have continued to make changes to reduce the amount of flex in the chassis. The primary part of the cars that presented the biggest flex problems was the right front corner. As time went on, the right front corner became stiffer. The problem we are faced with is that in many cases, the first part of the car to contact the concrete wall is the right front of the car.

7/13This fuel tank bladder is surrounded by a strong metal enclosure. Should this car experience a rear end impact, the fuel tank will stay in the car and the bladder will prevent fuel from spilling and igniting. Some car builders are now moving the fuel cell farther forward.

Brain injuries started to appear in the period between 1997 and 1999 when we saw several well-known drivers suffer serious brain-related injuries. The problems associated with the stiff chassis were beginning to show on a scale that was definitely noticeable. Then in 1999, teams were allowed to increase the wall thickness in the tubing that is a part of the front of the chassis. This further increased the stiffness of the front ends. It is obvious, with the tragedies we have seen, that today, the excessive amount of g-force transmitted to the drivers' bodies make crashes less survivable.

Many factors need to be addressed when considering the redesign of the cars. As we add structure and components to the cars in order to assist in dissipation of energy on impact, we need to also consider the effects each change has on the way the cars are setup and how those changes will affect the performance of the cars. For example, adding weight to the front of the car affects the weight distribution, which directly affects the handling and the way we set up the cars.

8/13The side bars should be placed as far away as is practical for the body type so that the driver is better protected from a side impact. Plating this area provides further protection from intrusion into the cockpit. Drivers have been speared by small diameter steel pieces used for attaching body panels.

If we decide to raise the framerail on the front of the cars to increase the angles formed by the tubing, we might alter the geometric layout that is so critical for camber control and roll center location. These two effects play a significant role in allowing the front tires to work the way they should. Correct designs for front geometry have evolved over many years and we don't need to destroy all of that work by overreacting.

As compromises to the above, it may be possible to move the engine back a little farther in order to compensate for the increase in weight to the front of the car to offset the effect of the added weight of the crush components.

We could angle the tubing at the front of the car in such a way that the geometry we have carefully designed into the cars remains the same. These are good examples of considerations that must be made during this process of change. Each proposed change must be carefully examined before implementation.

Changes are needed and we don't know exactly how far away we are from the solution to this problem. It is fairly safe to say that the more input the sanctioning bodies get from places like Detroit and other safety industry sources familiar with these kinds of problems, the sooner we can all breathe easier.

9/13Building a front clip that has shallow angles and that is braced excessively can cause the impact to be more severe on the driver. When the front end does not crush in a high speed, into-the-wall crash, the deceleration is very pronounced and the time from initial contact to the car stopping is shortened. This is directly translated into high g-forces of 50-70 g's or more as recorded in actual crash evaluation. Drivers subjected to 40 g's and greater stand a good chance of being killed without the proper safety equipment such as a head and neck restraint.

A lot of people are curious as to exactly what is wrong with the cars, how difficult it could possibly be to change them and exactly what are some of the proposed changes. Here are some thoughts and a bit of information that might help in understanding this complex predicament.

Stock cars need crush zones, period. Stock cars have traditionally not been designed with distinct crush zones. The crush zones should be built into areas of the car that have a good chance of coming in high-speed contact with the wall or other obstructions. The crush zones should collapse in a controlled way in order to slow the car and extend the time it takes to stop the car.

The way some stock cars collapse (or don't collapse as the case may be) makes it easy to understand why drivers can get hurt. The nose area of the car is supported with minimal structure and will provide little resistance when the car crashes into a concrete wall. As the nose is pushed back, the wall contacts the end of the front clip, or frame of the car.

The front clip, or frame portion of the front end is the part that has become overly stiff over the years. The speed the car is traveling when the actual frame reaches the wall is much the same as before the nose contacted the wall. Therefore the car stops in a very short distance and transmits excessive g-forces to the driver, just like what would happen to a stunt person if we were to take away the air bag in a 10 story fall.

10/13This is an example of how a car might be constructed to provide crush resistance all of the way from the front of the bumper to the engine. The bends in the framerails allow the frame to crush and resist the impact. The wall thickness of the main rail could be less forward of the front of the engine.

Ultra-straight front framerails will be a thing of the past in the near future as chassis designers move to design a more crush friendly chassis. Some of the current designs provide little protection for frontal impact and increase the liability for the car builder.

What we know from past research is that the cars need to crush with a constant resistance over a predetermined distance. That distance is directly dependant on the speed at which impact is made and the amount of g-forces the human body, or in our case, a driver's body with helmet attached, can withstand without serious injury.

Using the g-force limits and the maximum vector speeds (not necessarily forward speed but speed perpendicular to the wall), it has been written that we need a crush zone distance of between 2.2 and 3 feet. Coincidentally, in most racecars, there is almost exactly three feet between the front of the bumper and the front of the engine. The engine is considered by many to be the ultimate limit for how far the car will crush, as it will move very little on impact.

11/13The seat in a modern stock car needs to be installed inside a dedicated frame. That way it remains with the chassis and rollcage to protect the driver. Bolting the seat to the floor is not acceptable, even in stock class cars.

Within the overall crush zone there are two distinctly different areas to design for. The first is the area from the front edge of the bumper to the front of the framerail. Within this area, we could design a collapsible steel or aluminum structure similar to those that many production cars have.

All production cars are designed to crush like an accordion and they offer constant and equal resistance throughout the entire range of the crush zone. This reduces the g-forces transmitted to the occupants of the car.

A design that has been mentioned would be to place some material, similar to foam, between the front bumper and the framerails to absorb some of the impact. The properly designed system must provide adequate and constant resistance.

12/13The modern racing seat has not only rib support, but shoulder, side and rear head support. It will have reduced loss of shape and more support of legs. The head and neck restraint systems do a great job of reducing forward motion and we need side support also from the seat design.

The second area is the actual main frame. Once the car crushes back to the point where the ends of the framerail are, then the frame must take over and continue the resistance until the required crush zone design distance is used up. Too little resistance of the first zone and too much for the second zone equals high g-forces upon impact.

The most important elements in crush zone design are the amount of resistance of the crush zone structure and the ability of the structure to provide constant and equal resistance all during the crash, just like the stunt air bag.

If we could move the engine back farther from the front bumper, then we would have more room for the crush zone with an additional safety margin. That would increase the time of impact which would reduce the g-forces. This helps cars that are already front heavy and reduces the need to place lead weight in front of the driver, another bad idea.

13/13A head and neck restraint for dirt racing? You bet. You can never be sure you won't have a high g impact, even on dirt. Afterwards is too late to consider the consequences. If you suit up, you need a good restraint system.

Head restraints for lateral movement that are built into the seats for super speedway cars have evolved into much stronger and efficient designs. The better devices offer an extended range of protection while enabling the driver to see to the side of the car. Limitation of lateral head movement is a safety goal of those who manufacture racing seats.

The sanctioning bodies and track officials for all of stock car racing need to act now. They need to fully understand how we have come to this point, how important it is to quickly evaluate their own particular safety situation and then put together a list of changes that will be responsible and effective. If they can do that, then once all is said and done, the losses we have suffered as a community will not be in vain.

Do your individual part by buying and using a quality head and neck restraint, a modern, well-designed seat, a highly-rated fire suit and racing approved helmet, and above all, a car that will dissipate energy in a hard crash. Let your car builder know that you are concerned about your safety. Create your safe-er environment today.